Slightly modify the formatting rules for braced lists.

Basically, the new rule is: The opening "{" always has to be on the
same line as the first element if the braced list is nested
(e.g. in another braced list or in a function).

The solution that clang-format produces almost always adheres to this
rule anyway and this makes clang-format significantly faster for larger
lists. Added a test cases for the only exception I could find
(which doesn't seem to be very important at first sight).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@182082 91177308-0d34-0410-b5e6-96231b3b80d8
[analyzer; alternate edges] improve support for edges with PseudoObjectExprs.

This optimizes some spurious edges resulting from PseudoObjectExprs.
This required far more changes than I anticipated.  The current
ParentMap does not record any hierarchy information between
a PseudoObjectExpr and its *semantic* expressions that may be
wrapped in OpaqueValueExprs, which are the expressions actually
laid out in the CFG.  This means the arrow pruning logic could
not map from an expression to its containing PseudoObjectExprs.

To solve this, this patch adds a variant of ParentMap that
returns the "semantic" parentage of expressions (essentially
as they are viewed by the CFG).  This alternate ParentMap is then
used by the arrow reducing logic to identify edges into pseudo
object expressions, and then eliminate them.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@182083 91177308-0d34-0410-b5e6-96231b3b80d8